Machines for packaging article goods, especially envelope packaging machines have a feeding table, onto which the goods to be packaged are introduced one after the other by means of a conveyor. The conveyor pushes continuously the articles in a form of a stack forwardly to the table in such a way that they are in approximately upright position with their lower edges against the table surface. For automatic grouping and packaging of goods of this kind, batches of certain size are separated from the front end of the advancing stack by means of special separating means. These batches are pushed aside by a pusher to an aftertreatment unit that is located adjacent to the table. An automatically operated apparatus of this kind is known, for example, from a co-pending U.S. patent application Ser. No. 08/682,718 "Apparatus for separating a stack portion with a separator element and a device for gripping a protruding marker" filed on Jul. 29, 1996 and based on International Application No. PCT/FI95/00032. This application is assigned to the Assignee of the present invention and it is incorporated herein by reference. The problem with automatic apparatuses is that they are not suitable for manual packaging. In order to perform manual packaging, either the pushing device comprising the separating means and the pusher itself has to be demounted, or another manual line has to be provided in addition to the automatic one. U.S. Pat. No. 4,884,675 shows a grouping device receiving letter envelopes directly from an envelope production machine. The grouping device is pivotable in a horizontal direction away from a position above the table to a position where it allows free access to the table for manual operation. However, in the apparatus there is often need for several operations at the usual working height of approximately 0.6 to 1.1 m. The horizontally pivotable construction requires space in the packaging apparatus, which needs several accessories which must be placed at a suitable height to be accessible for example for maintenance and adjustments.